How can elephants be carefully prevented from plundering plantations? Apparently through the smell of a lion, a study shows: experiments show that African elephants shy away from certain volatile substances from the feces of big cats. These odorous substances can also be produced artificially. They are therefore suitable as a basis for an inexpensive elephant repellent that could benefit the protection of small farmers and thus the endangered pachyderms themselves. Since lion and tiger smells are very similar, the substance probably also scares off Asian elephants, say the researchers.
Peaceful coexistence is the key: it is well known that the support of the local population is of key importance for elephant protection. But there is a big problem with this: From the perspective of small farmers in Africa and Southeast Asia, elephant herds pose a threat to their livelihood. One can easily imagine what a field or an orchard looks like after the giants have trampled and munched through them. The proboscis repeatedly cause great economic damage and the destruction of their natural habitats exacerbates the problem more and more: in search of food, they invade human settlements and cultivated areas with increasing frequency. This leads to conflicts, some of which end with fatal shots. Because so far there are no effective measures to keep elephants away from crops and at the same time protect their populations.
From mosquito to elephant
But now the researchers around Omer Nevo from the University of Ulm are reporting a possible solution to the problem. According to this, elephants can be deterred in a way that is known from the fight against mosquitoes: by a so-called repellent. “Elephants are very odor-oriented animals – so negative, fearful smells could be the key to keeping them permanently out of fields,” explains Nevo. Odors from predators come into question. In the case of the elephants, these are lions or, in Asia, the tigers, because at least young animals have to fear these big cats. “We suspected that smells associated with such predators and their excretions trigger fear reactions in the elephants and cause them to retreat,” says co-author Manfred Ayasse from Ulm University.
To what extent this is the case, the scientists have now explored in the case of the African elephant. To do this, they confronted five semi-tame elephants from a reserve with perforated PVC pipes filled with cotton threads. These carrier substances were “scented” with various odorous substances. In addition to lion droppings, the biologists used faeces from cheetahs, dogs and giraffes as controls. The PVC pipe, which was enriched with an odorous substance, was placed on a path so that the elephants could not move to the side – so they had to cross the obstacles. The keepers tried to get the animals to cross the respective pipe with shouts or rewards.
Lion smell stinks the elephant
In the case of the smell of faeces from cheetahs, dogs or even giraffes, the test animals did not shy away from stepping over the pipes. In the case of the lion excrement smell, however, the reactions were clear, the researchers report: One male elephant even ran away and the other pachyderms also showed very strong avoidance behavior. Even juicy oranges couldn’t get them to cross the lion-smelling pipe, the researchers report.
Through laboratory tests, they were able to show that the components phenol and indole are responsible for the characteristic smell of lion droppings. A repetition of the behavioral experiment with the PVC pipes then proved that these substances are actually decisive: the elephants were deterred by these components as well as by the lion droppings themselves. This is an important aspect, because phenol and indole are freely available and inexpensive. They are therefore suitable for making a repellent.
The scientists now hope that the results can be used to develop a gentle approach to avoiding human-elephant conflicts: Possibly, the use of the substance on the edge of plantations can prevent devastation by elephants in the long term. The researchers also believe that the natural repellent is also effective against Asian elephants. Because, as they report, the faeces of the native tigers there also contain phenol and indole. Further investigations must now show whether the process actually delivers what it promises.
Source: Ulm University, specialist article: Conservation Science and Practice, doi: 10.1111 / csp2.306